Mercury switch metal clip type



MERCURY SWITCH METAL CLIP TYPE Filed Nov. 24, 1928 INDENTOR.

ATTORNEIJ,

Patented Oct. 13, 1931 UNITED STATES PATENT. OFFICE TO MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF

805134, A CORPORATION OF DELAWARE mmnnaroms, mun- MEBOURY SWITCH METAL CLIP TYPE Application filed November 24, 1928. Serial No. 821,567.

This invention relates in general to mercury switches and more particularly to mercury switches of the type which has a mercury to mercury make and break occurring on the surface of the protective element of arc resistant material. r a

This typevof mercury switch usually comprises an outer envelope which may be of soft glass orother suitable material. I Within the outer envelope is a protective element of arc resistant material which may be hard glass, porcelain, quartz, molded aluminum oxide or any other composition or. substance capable of withstanding the high temperatures and rapid temperature fluctuation as well as the other destructive forces set up by the arcing and tending to break down the structure of the switch. Usually such a protective element is in the form of a sleeve or cup. In

the present application, the protective element shown is embodied in various types of cup structures and each cup operates as a trap to confine a body of mercury. The mercury also has a shiftable portion which makes and breaks contact with the mercury in the cup on the surface of the cup.

Thefproblem of pro rl mounting a cup of this character within t e outer envelope has given rise to a great deal of annoyance and difliculty. The materials of the outer envelope and'of the cup have different coeflicients of expansion and the heating and cooling occurrlng in the use of the switch will result in breakage or fracture of the elements of the switch if theseparts directly contact with each other without sufficient clearance to allow for difl'erential expansion and contraction. I

One of the principal objects of the present 40 invention is to provide a novel and effective means of supporting or holding a protectlve element in proper position within the outer envelope while relieving the outer envelope of shocks and strains incident to arcing. 46 Along with these advantages the present inand easy assembly. Further, the construcvention provides an extremely simple and comparatively inexpensive constructlon and 1s of such nature as to lend itself'to efficient manufacturing process and to permit quick 1 50 tion is so sturdy and durable and so adapted to the requirements of the problem that it will stand up when in use over a long period. Other objects and advantages reside in certain novel features of the construction, arrangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, and in which:

' Figure 1 is a view in central vertical longitudinal section showing one embodiment of the invention and illustrating the switches positioned when the ortions of the mercury are just about to ma e contact on a surface of the protective cup;

Figure 2 is a similar view illustrating the switch tilted just beyond the position indicated ,in Figure 1 with the portions of the mercury in contact or united;

Figure 3 is a plan view of the internal structure of the switch shown in Figures 1 and 2 with the outer envelope shown in hori: zontal section;

Figure 4 is a View in central vertical lonitudinal section showing a slightly difler- .ent type of switch and illustrating the switch so positioned that the shiftable portion of the mercury is out of contact with the mar: cury in bot cups;

Figure 5 is a view similar to Figure 4 but illustrating the switch position so that the shiftable portion of the mercury makes contact with the, portion of the mercury in onep;

Figure illustrating switch;

Figure 6 is a view similar to Figure 5 but the reverse position of the 7 is a plan view of the switch of holders of the cups shown in Figure 7; and

Figure 10 is a view similar to Figure 9 showing the cup holder construction of Figures 1 to 7 inclusive.

Referring to the drawings and more particularly to Figures 1 to 3,,inclusive, the numeral 1 designates an outer envelope which may be of soft glass or any other appropriate or suitable material. A protective element in the form of a cup 2 of hard glass, porcelain, quartz or other are resistant material is positioned within the outer envelope and is located out of contact of the walls thereof. For supporting and holding the cup 2 in proper position and relation to the envelope 1 a spring clip 3 is prpvided and consists of a split ring of stainless ferreous metal such as stainless steel or other suitable spring material. Opposite its split the ring 3 is formed with an outwardly and upwardly inclined holding arm 4 terminating in a socketed end 5 which receives the cup 2 and is cemented thereto as at 6. The spring clip 3 is resilient and itis tensioned slightly so that under the influence of its inherent resiliency it expands and frictionally grips the inner wall of the envelope 1 when it is assembled therewith. A body of mercury is placed in the envelope 1 and has a portion 7a confined in the trap constituted by the cup 2 and also has a shiftable portion 7 1) disposed in the envelope, outside of the cup and making and breaking contact with the por tion 7a as the switch is operated. An elec" trode 8 is sealed in through the upper portion of the peripheral wall of the envelope and extends down into the mercury 7a in the cup 2. Another electrode 9 is sealed in through one end of the wall of the envelope 1 and is immersed in the portion 7 b of the envelope in all The cup 2 has a cylin rical portion 2a and a closed bottom 26. The cylindrical portion 2a is cut away for a portion of its periphery at a point spaced from its upper end and from the bottom of the cup to provide an opening 10 through the peripheral wall of the cup and to form above this opening a shield 11 for the electrode 8, the 'shield being pressed inwardly toward the electrode whereby to better protect the same and to leave the clearance necessary for the unobstructed mercury movements necessary for making and breaking contact between the two portions of the mercury. As will be understood from Figures 1 and 2, the two .ortions 7a and 7b of the mercury make and reak contact over ositions of the switch.

the lip 2 constituted by the lower mar inal wall .of the opening 10 in the body 0 the 7 rents. If the surface is left rough or merely ground, slotting under the influence of the are rapidly progresses. The spring clip and holder thus described is not effected'by the mercury or by the arc and yet it very effectively holds the protective element in properposition within the envelope 1 and out of contact therewith. It prevents the transmission of shocks and strains between the protective element and the outer envelope and thereby prevents breakage.

In the form of theinvent'ion shown at Figures 4, 5, and 6, the outer envelope of the switch is designated at 15 and may be of soft glass or other material. In this type of switch two protective elements or cups 16 and 17 are provided and as before are constituted of arc resisting material. The cups 16 and 17 are fitted and connected or secured as at 18a in sockets 18 and 19 formed on a double arm integral with a spring clip 22 which as in the previous embodiment comprises a split metal ring. In this embodiment of the invention, however, the ring or clip 22 is only of approximately circular form, the portion of the ring contiguous with the arm 20 being of the same flat formation as these arms. A body of mercury is placed in the envelope 15 and has portions 20a and 20b filling the cups 16 and 17 respectively, and also has a portion 200 which is shifta-b-le in the envelope and alternately makes and breaks contact with the mercury 20a and 20b in the cups 16 and 17 respectively. Electrodes 23,

24 and 25 are sealed through the outer envelope 15 and are immersed in the portions 20a, 20b and 200 respectively of the mercury. The electrodes 23 and 24 project down through the upper open ends of the cups 16 and 17 into the mercury therein and are equipped with glass shields 27 which operate toprevent direct contact between the shiftable portion of the mercury and the electrodes. In this construction as in the previous embodiment of the invention the spring clip and holding means associated therewith operates to maintain the protective elements which receive the are out of contact with the outer envelope and prevent the transmission of shocks and strains between the protective cups and the envelope. When this switch is rocked to the position shown in Figure 5, the shiftable portion. 200 of the mercury makes contact with the portion 204; over the lip of the cup 16 which may be glazed as in the previous embodiment of the invention. When the switch isrocked in an opposite direction, or to the position shown in Figure 5, the shiftable portion 200 of the mercury makes contact with the portion 20b confined in the cup 17.

Obviously various means may be provided for suitably attaching or securing the cups or protective elements to the spring clips or retaining elements. Thus, in lieu of cementing the cups to the sockets formed at the ends of the holding arm integral with the spring clips, each socket member may be split and constituted to provide resilient retaining or gripping jaws as shown at 30 in Figures 7, 8 and 9, the jaws 30 snapping into a peripheral groove 31 provided in the associated protective cup. A

In all embodiments of the invention the protective elements or cups are held in proper position within the outer envelope by means of a clip which is preferably constituted of spring metal and which cooperates wi.h the envelope and with the cups tomaintain the cups in proper position. The protective elements and clips are completely made up outside of the envelope and may be easily assembled therein prior to the closingof the ends of the envelope. In this connection it is to be understood that the envelope in its ordinary form is usually a tube with open ends. After the protective cups on the clips are assembled within the tube the ends of thetube are closed and the electrodes sealed therein. As illustrated in the drawings each envelope has the usual tubulation through which the mercury is introduced, the air exhausted and the inner gas introduced. Finally the tubulation is closed. As this is an established practice no further detailed explanation is necessary.

The invention claimed is:

1. A mercury switch comprising an outer envelope, a trap of arc-resistant material therein, a body of mercury'havin a portion confined in said trap and a shifta le portion making and breaking contact with the ortion in the trap, and means forv holding t e trap in position in the envelope including a resilient metallic ring like retaining element tensioned to frictionally engage the envelope and cooperable with the trap.

2. A mercury switch comprising an outer envelope, a protective element of arc resistant material in said. envelope, and a spring clip of stainless ferreous metal and of band-like structure for holding said protective element in position. A

3. A mercury switch comprising an outer envelope, a protective elementof are resistant material in said envelope, a body of mercury in said envelope having portions making and breaking contact on a surface of said protective element, and a splitexpansible retaining ring tensioned to frictionally engage the inner wall of the envelope and in holding relation to said protective element.

4. A mercury switch comprising an outer envelope, a trap of are resistant material therein, a body of mercury having a portion confined in the trap and a shiftable portion making and breaking contact with the portion in the trap,.a spring clip within the envelopeand engaged with the inner wall thereof, and a holder carried by the spring clip and supporting said trap.

5. A mercury switch comprising an outer envelope, an element therein carrying a cup of are resistant material, a spring clip coacting with said envelope and said element for holding the cup in proper position in the envelope, said spring clip being flexible relative to the outer envelope although frictionally engaged.

therewith, and a body of mercury having a portion filling the cup and a shiftable portion making and breaking contact with the portion in the cup over a lip of the cup.

. 6. A mercury switch including an outer envelope, a protective cup of arc resistant material in saidenvelope, and a spring clip engaged with the envelope and having an arm formed with a socketed portion receiving and secured to the cup.

7 'A mercury switch comprising an outer envelope, a pair of cups of are resistant material, an arm carrying said cups and disposingsaid cups in spaced relation within the envelope and a flexible spring clip cooperable with the envelope and with the arm for holding the cups in proper position of the enveope.

8. A mercury switch comprising an outer v envelope, spaced traps of are resistant material located' within the outer envelope, an

arm having socketed ends receiving and secured to said traps, a resilient retaining element coacting with an intermediate portion of the arm and with the envelope for holding the traps in proper position in the envelope,

a body of mercury in the envelope having por-' portionv tions filling the traps and a shiftable making and breaking contact with t e portions in the traps, electrodes sealed through the outer envelope and immersed in the portions of the mercury in the traps and an electrode sealed through the outer envelope and constantly immersed in the shiftable portion of the mercury.

9. A mercury switch comprising an outer envelope, a trap of are resistant material therein and a spring clip tensioned to expand and frictionally engage the outer envelope and having an integral arm terminating in a :ocket' which receives .and is secured to the '10. A mercury switch comprising an outer envelope, a trap of are resistant material.

therein, a resilient clip tensioned to expand and engage the inner wall of the outer envelope, and an arm integral with the clip and 4' t g i having means for engaging and-supporting I thetra I .11. if mercury switch comprising an outer envelope, spaced tra s of are resistant ma- 5 terial therein, a resi ient'clip' enga edwith the envelope and located between t e tra s, and a dquble arm integral with the clip, spaced from the outer envelo e and having means to engage and supportt e traps.

v 10 In witness whereof, I have hereto afiixed my signature.

PAUL K. ORAMBLET. 

